Kneading pump



y 1956 F. KLEINLEIN 2,745,643

KNEADING PUMP Filed Sept. 2, 1952 2 Sheets-Sheet 1 INVENTOR. FRI'TZ KLEINL EIN y 1956 F. KLEINLEIN 2,745,643

KNEADING PUMP Filed Sept. 2, 1952 2 Sheets-Sheet 2 i INVENTOR.

F'JF/TZ KL Ef/VL E/IV United States Patent KNEAnnso PUMP Fritz Kleinlein, Forth, Germany, assignor to Martin Scheerle, Steckborn, Switzerland Application September 2, 1952, Serial No. 307,533 Claims priority, application Germany May 2, 1952 8 Claims. (Cl. 259-104) The present invention relates to a kneading pump. Such pumps have been used for some time for mixing, kneading and simultaneously displacing against a higher pressure various substances of highly viscous, plastic and in certain cases also of powdered consistence.

Most known pumps of this kind comprise two or more worms engaging each other and rotatably mounted in a housing in which they rotate in the same or in opposite direction according to construction. Care has always been taken to provide a good sealing engagement between the helical flights of the cooperating worms throughout their length or at least towards their delivery end, and to ensure that considerable kneading of the material passing through the pump is brought about by changes of volume of the chambers formed in the worm grooves while the said material is advanced'through these grooves. However, the harder the kneadable masses to "be treated have become, whether they were artificial thermoplastic materials or rubber mixtures, the more constructive, and at the same time working difliculties arose. Substantial power means are required for driving the worms of such machines and the starting stresses lead to important torsional and bending stresses of the power transmitting elements. In view of the given outer diameter and consequently given dimensions of the housing these stresses can only be obviated by reinforcing the inner diameter i. e. the diameter of the core of the worms. This results in reduced volumes of the chambers and consequently in a substantial retrogression of the output of such machines. At the same time the capacity of such machines to automatically draw-in the masses to be kneaded becomes very weak.

According to the present invention the inner diameter i. e. the diameter of the core of the worms is enlarged and approximated to the outer diameter thus giving to the worms a high torsion and bending strength while the dimensions of the housing may remain the same.

It is an object of the present invention to provide worms having relatively slim flights of a special shape given in consideration of a rotatable supporting of the worms in the recess of the housing and of an optimum conveying and kneading eflect.

Kneading pumps according to my invention open entirely new possibilities in the worldng up of rubber and plastic material. It is for example possible to directly work up or gelatinate softened or not softened polyvinylchlorid, co-polymerides or mixtares of polymers with other materials in order to feed calenders, spraying machines or die presses.

It is a further object of my invention to provide a kneading pump which can be used as a jet moulding machine enabling a blister-free spraying of practically all modern jet moulding masses such as polyvinyl-chlorid, copolymerides, polyethylene, polyamides etc.

It is a special feature of my kneading pump that it has a high output and provides an excellent kneading effect on plastic materials and rubber-like masses. This knead ing pump takes over in a very rational, simple and con- 2,745,643 Patented May 15, 1956 tinuous way the work of expensive masticator rolling mills or kneading machines which otherwise must be used, such as for example for the reduction of rubber in order to obtain rubber solutions, or for obtaining homogeneous rubber mixtures or polyviuyl-chlorid pastes, for gelatinating and spraying polyvinyl-chlorid pastes, for coloring mixtures of polyvinyl-chlorid or other mixtures etc.

Several embodiments of my invention are shown, by way of example, in the accompanying drawing in which:

Fig. 1 is a plan view, partly in section, of a kneading pump showing the pump housing, the inlet and outlet for the masses and two intersecting worms adapted to rotate in opposite directions.

Fig. 2 is a section according to the line llll of Fig. 1;

Fig. 3 is a section according to the line Ill-4H of Fig. 1;

Fig. 4 shows a plan view of a second embodiment having two intersecting worms with cylindrical cores;

Figs. 5 and 6 are two further embodiments in which the cores of the worms are partly cylindrical and partly conical and Fig. 7 shows an embodiment in which the core of one worm is conical while the one of the other worm is cylindrical.

In the embodiment shown in the Figs. 1, 2 and 3, the numeral 1 designates a housing which provides a recess bounded by two surfaces of rotation having parallel axes and intersecting each other. Said recess is adapted to receive a left-handed worm 2 and a right-handed worm 3 having each a cylindrical core and being provided each with a. helical flight 4 and 5 respectively, on their core. The helically contoured outer surfaces of rotation 6 and 7 respectively, of said flight are of substantially equal diameter as the corresponding cylindrical surfaces bounding the recess of the housing 1, thus rotatably supporting each worm in said recess. The helical flight 4 of the Worm 2 is stepped to provide a second helically contoured cylindrical surface 8 immediately adjacent to and of smaller diameter as the first cylindrical surface 6. Likewise, the helical flight 5 of the worm 3 is stepped to form a helically contoured cylindrical surface 9 of smaller diameter but of the same pitch as the cylindrical surface 7. The sur faces 6 of the worm 2 coact with the surfaces 9 of the stepped flight 5 of worm 3, while the surfaces 7 of the last-mentioned worm 3 engage the stepped surfaces 8 of the worm 2, thus producing, in spite of the narrow construction of the flights 4 and 5 respectively, a strong support of the worms in the recess and a suflicient tightness for a good conveying of the material to be kneaded.

In a second embodiment shown in Fig. 4 there are again two worms 10 and 11 comprising each a helical, stepped flight and a cylindrical core. The ditference with regard to the first described embodiment lies in the fact that in this embodiment the chambers formed in the worm grooves have different volumes. For this purpose the left-handed worm 10 has, on a first portion 12 of its length, a first helical flight 13 to provide a first helically contoured cylindrical surface of substantially equal diameter as the cylindrical surfaces bounding the recess of the not shown pump housing. Said flight 13 is stepped as at 14 to provide a second helically contoured cylindrical surface of smaller diameter than the firstmentioned surface. The said portion 12 of the length of the worm 10 further has a second helical flight 15, providing a helically contoured cylindrical surface of equal diameter as the one provided by the flight 13, but having a somewhat greater pitch. On a portion 16 of its length the worm 16 has a single helical flight l7 continuing the cylindrical surface of the flight 15 of the portion 12 of the worm 10 and tapering in width away from said portion 12. In this portion 16 a flight stepped as at 19 independently continues the stepped 3 flight 13, 14 of portion 12 of the worm 10. The second worm 11 in this embodiment has two portions similar to the two portions of worm 10, whereby the portion 29 of worm ll corresponds to the portion 12 of worm 1d and portion 21 of worm ll corresponds to the portion 16 of worm it portion 2i, being arranged adjacent to portion 16 and portion 21 being arranged adjacent to portion 12 in such a manner that the stepped portions l4, 19 of the helical flight of worm it) cooperate with the corresponding flights 22, 2.3 of worm l1 and the flights l5, 11.7 of worm it) cooperate with the corresponding stepped portions 24, 25 of the flights of worm 11. This system of flights produces a plurality of various chambers in the grooves of the flights which help in intensifying the mixing and kneading effect.

In the thi d embodiment shown in Fig. 5 the arrangement of the ped flights 26 and 27 respectively, on the cores 2 3 and M respectively, of the worms is the same as in the embodiment described with respect to Fig. l of the drawings. The cores, however, of the worms are intermittently conical and then cylindrical as, for example for the worm 28 the core is cylindrical over the portion 3%) conical over the portion 31 of its length. The core 29 of the other worm is conical over the portion of its length adjacent to and cooperating with the cylindrical portion 3% of the first worm, and cylindrical over that portion of its length adjacent to the conical portion 31 of the first worm. Thus the mass entering the pump in direction of the arrow A is pressed during its passage through the portion 30 first into the worm 28 and afterwards during its passage through the portion 31 into the worm 29 and is thereby intensely kneaded and mixed. This alternation of cylindrical and conical portions may be repeated as often as desired throughout the length of the pump.

The embodiment shown in Fig. 6 provides two worms 32 and 33. The core of the worm 32 is cylindrical over a certain portion of its length as at 34, and adjacent to a corresponding conical portion 35 of the core of the worm 33. The same worm 32 is conical as at 36 over another portion of its length which portion on its turn is adjacent to a cylindrical portion 37 of the core of worm 33. The conical portions of both worms 32 and 33 are provided with a pair of parallel, helical flights 38, 39 for worm 32 and 4t 41 for worm 33 each providing a helically contoured cylindrical surface of substantially equal diameter as the cylindrical surfaces bounding the recess of the not shown housing for rotatably supporting the worms in said recess. intermediate the said two flights 38, 39 and 49, 41 respectively, on the conical portion of the worms a third helically contoured surface 42, ,3 for worm 33) is provided, the diameter of which is substantially smaller than the one of the flights 38, 39

of worm 32 and 40, 41, respectively. The cylindrical portion of the core of the worms is provided with a single helical flight as at 3-4 and 45 for supporting the worm in the recess of its housing and for engaging between the two parallel flights on the conical portion of the adjacent I worm, thus forming a tight sealing between the grooves situated between the flights. Here too, as in the embodiment according to Fig. 5, the mass is forced into a to and fro movement resulting in excellent kneading effects.

The embodiment according to Fig. 7 has very small chambers through which the masses to be kneaded may pass thus producing a slow but highly eflicient kneading. In this embodiment the core of one worm, designated with the numeral 3-6 is cylindrical throughout its length and provided, with a single helical flight 47 providing a helically contoured cylindrical surface of equal diameter as the one bounding the recess in the housing for the worms for rotatably supporting the worm in the recess. 47 engages a groove 4% formed between a pair of parallel, helical flights 49, 50 provided on the conical cores of the other worm 51. This pair of helical flights 49, 50

contacts the cylindrical core of the worm 46 thus providing a tight sealing between the chambers.

What I claim is:

l. A kneading pump comprising a housing which provides a recess bounded by two cylindrical surfaces having parallel axes and intersecting each other, two Worms each having a core and a system of helical flights on said core, said system comprising, on a first portion of the length of the worm, a first helical flight stepped to provide a first helically contoured cylindrical surface of substantially equal diameter as the one of the said cylindrical surfaces bounding the recess in the housing for rotatably supporting the worm in said recess, and to provide a second helically contoured cylindrical surface of smaller diameter than the first such surface, and a second helical flight having a helically contoured cylindrical surface of equal diameter as the said first surface of the first helical flight, the pitch of the said second helical flight and of the contour of its helically contoured cylindrical surface being greater than that of the first helical flight and of its first helically contoured cylindrical surface, respectively, said system further comprising, on a second portion of the length of the worm, a single helical flight stepped to provide a helically contoured cylindrical surface tapering in width away from said first portion and continuing both the said first cylindrical surface of said first flight and the said cylindrical surface of the second flight of said first portion, and a second helically contoured cylindrical surface continuing the said second helically contoured cylindrical surface of the first flight of said first portion, the first portion of each worm being arranged adjacent the second portion of the other worm in said recess of the housing, whereby the first cylindrical surface of the first flight of the first portion and the first cylindrical surface of the flight of the second portion of each worm cooperate with the second cylindrical surface of the second portion and of the first portion, respectively, of the other worm.

2. A kneading pump comprising a housing which provides a recess bounded by two cylindrical surfaces having parallelaxes and intersecting each other, two worms each having a core and, on said core, on at least one portion of the length of the worm, a pair of parallel helical flights each providing a helically contoured cylindrical surface of substantially equal diameter as the one of the said cylin drical surfaces bounding said recess in the housing for rotatably supporting the worm in said recess, and, intermediate the said two helical flights of the pair, a third helically contoured cylindrical surface, each of said two worms further having, on at least one other portion of the length'of the worm, a single helical flight providing a helically contoured cylindrical surface of equal diameter as the aforesaid helically contoured cylindrical surfaces on the said two parallel flights of the said one portion of the worm, for supporting the worm in said recess, the said one portion of each worm being arranged adjacent the said other portion of the other worm in said recess of the housing, the said cylindrical surface on the said other portion of each worm engaging the said third cylindrical surface intermediate the two flights of the said one portion of the other worm.

3. A kneading pump as claimed in claim 2 in which the said core of each worm is conical on at least part of the said one portion of its length, between the turns of the said pair of flights, and is cylindrical on at least part of thesaid other portion of its length between the turns of the said single flight.

4. A kneading pump as claimed in claim 3 in which the maximum diameter of the core, in its conical portion, is greater than the diameter of the said third helically contoured cylindrical surface. I

5. A kneading pump as claimed in claim 3 in which'the said helically contoured cylindrical surfaces on the said pair of parallel helical flights of the said one portion of the length of one worm contact the cylindrical core of the said other portion of the length of the other worm.

6. A kneading pump comprising a housing defining an elongated recess bounded by at least two surfaces of rotation having parallel axes and uniform equal radii intersecting each other longitudinally, at least two worms disposed in said recess with their axes parallel to each other and respectively coincident with the axes of said surfaces of rotation, said worms each having a core and a helical flight on said core, said flight having a helically contoured outer surface of rotation substantially conforming to and slidably engaging the respective recess surface and r0- tatably supporting the worm in said recess and providing helically extending kneading spaces extending from one end of the recess to the other, the flights of said worms being in peripheral engagement with the kneading spaces therebetween being in tangential relation and having open communication with each other, the flight of at least one of said worms being stepped to provide at least a second helically contoured surface of rotation of different diameter than that of the first-mentioned outer surface of the flight of said one Worm, said second helically contoured surface of rotation of said one worm peripherally engaging the first-mentioned helically contoured outer surface of rotation of the flight of at least one other worm.

7. A kneading pump comprising a housing defining an elongated recess bounded by at least two cylindrical surfaces having parallel axes and uniform equal radii intersecting each other longitudinally, at least two Worms disposed in said recess with their axes parallel to each other and respectively coincident with the axes of said cylindrical surfaces, said worms each having a core and a helical flight on said core, said flight having a helically contoured outer cylindrical surface of substantially conforming equal diameter as that of the respective recess surface and rotatably supporting the worm in said recess and providing helically extending kneading spaces extending from one end of the recess to the other, the flights of said worms being in peripheral engagement with the kneading spaces therebetween being in tangential relation and having open communication with each other, the flight of at least one of said worms being stepped to provide at least a second helically contoured cylindrical surface of different diameter than that of the first-mentioned outer surface of the flight of said one worm, said second helically contoured cylindrical surface of said one worm peripherally engaging the first-mentioned helically contoured outer cylindrical surface of the flight of at least one other Worm.

8. A kneading pump as claimed in claim 7 in which the said core is conical on at least one portion and cylindrical on at least one other portion of the length of each worm, the said one portion of one worm being adjacent to the said other portion of the other worm, and vice versa.

References Cited in the file of this patent UNITED STATES PATENTS 1,423,768 Holdaway July 25, 1922 2,119,162 Hartner May 31, 1938 2,231,357 Burghauser et al. Feb. 11, 1944 

